Polylactic Acid (PLA), Khawv koob ntawm Kev Hloov Cov qoob loo rau hauv yas

Polylactic acid yog cov khoom siv polyester aliphatic muab tau los ntawm biomass, uas muaj biocompatibility zoo thiab biodegradability, thiab muaj qhov zoo ntawm cov neeg kho tshuab muaj zog, zoo pob tshab, yooj yim ua thiab molding, thiab yog qhov loj tshaj plaws hluavtaws degradable yas hauv industrialization.
Polylactic acid tuaj yeem npaj los ntawm lub cev qhuav dej ncaj qha polycondensation ntawm lactic acid thiab lub nplhaib-qhib polymerization ntawm lactide (cyclic dimer ntawm lactic acid).
PLA yog aliphatic polyester tsim los ntawm lactic acid los ntawm oligomerization, cyclization, polymerization thiab lwm yam txheej txheem. Cov txheej txheem hloov pauv ntawm PLA yog raws li hauv qab no: cov kws kho mob tuaj yeem ua tau zoo ua LA los ntawm cov hmoov txhuv nplej siab los ntawm cov qoob loo xws li pob kws los ntawm hydrolysis thiab microbial fermentation, thiab ntxiv hloov mus rau hauv PLA los ntawm kev sib xyaw ua ke polymerization lossis lub nplhaib-qhib polymerization, paub txog "magic" ntawm kev hloov cov qoob loo rau hauv cov yas.

Txij li thaum LA monomer muaj ob pawg hydroxyl (-OH) thiab carboxyl pawg, nws tuaj yeem sib xyaw nrog cov carboxyl thiab hydroxyl pawg ntawm lwm LA monomer, raws li. Nyob rau hauv txoj kev no, LA monomers hloov pauv kom tau txais cov khoom hnyav molecular PLA.

Tam sim no, lub ntsiab lag luam polylactic acid yog poly-L-lactic acid (PLLA). Lactic acid yog chiral molecule uas muaj ob isomers, L-lactic acid (L-lactate) thiab D-lactic acid (D-lactate). Nyob rau hauv cov txheej txheem ntawm polylactic acid ntau lawm, L-lactic acid chav tsev hloov mus rau D-lactic acid chav tsev vim yog qhov kub thiab txias, catalyst thiab lwm yam, uas thaum kawg ua rau qhov nce ntawm D-lactic acid unit thiab txo qis. ntawm nws qhov theoretical optical rotation tus nqi hauv PLLA.